This is a report of a study in two parts, one on teaching and the other on learning. The subjects of the first part were sixth graders in two different programs, one a core program and the other an immersion program. The subjects of the learning study were secondary school students and adults. The purpose of the study was: (1) to develop appropriate research methodologies, (2) to understand language teaching and learning processes by observing them under different conditions, and (3) to indicate the possible interrelations between teaching and learning in formal classrooms. Each part of the investigation describes the relevant research model and reports on the application of the model to some issues, specifically, the effects of the learning setting, the age of the learner and the attained level of proficiency. The instrument in the teaching section analyzes teaching activities and the discourse functions that characterize the verbal interaction between teacher and students. The learning study model attempts to account for the way in which information about the language is assimilated by the learner, represented by the learner as knowledge, and then used to form language responses. The teaching instrument identifies some essential differences in language teaching in the two types of classes; the learning model indicated that explicit and implicit information about language have unique roles in the solution of specific language tasks. (Author/AMH)